1. Field of the Invention
The present invention relates to a recording medium suitable for use in recording using water-based inks and an image forming process using this recording medium. In particular, the present invention relates to a recording medium which permits forming images high in optical density, bright in color tone and high in resolution, and has excellent ink absorbency. The present invention also relates to an image forming process using such a recording medium. The images recorded on the recording medium of the present invention have excellent shelf stability.
2. Related Background Art
An ink-jet recording system is a system in which minute droplets of an ink (recording liquid) are ejected by any one of various working principles to be applied to a recording medium such as paper, thereby making a record of images, characters and/or the like. In an ink-let recording system, recording can be conducted at high speed and with a low noise, multi-color images can be formed with ease, recording patterns are very flexible, and development is unnecessary. The ink-jet recording system has been developed into information instruments led by printers and including copying machines, word processors, facsimiles and plotters. In recent years, high-performance digital cameras, digital video cameras and scanners have begun to be provided cheaply, and printers using an ink-jet recording system have been preferably used in output of image information obtained from these instruments together with the use of personal computers. As a result, there is a demand for simply and easily outputting by an ink-jet system images comparable in quality with silver salt photographs and multi-color prints by a plate making system.
Improvements in structures and recording systems of printers, such as speeding up and high definition of recording, and full-coloring of images, have been made in order to meet such demand. Improvements in structure and properties of recording media have also been investigated extensively.
With respect to recording media used in ink-jet recording and the like, a wide variety of recording media has heretofore been proposed. For example, Japanese Patent Application Laid-Open No. 52-9074 discloses recording media provided with, as an ink-receiving layer, a layer comprising a silica pigment having a great specific surface area as a main component for improving the ink-absorbing rate thereof and having voids, and Japanese Patent Application Laid-Open No. 63-22997 discloses recording media, in which voids in a pigment layer forming an ink-receiving layer are controlled. Japanese Patent Application Laid-Open Nos. 55-51583 and 56-157 describe the fact that non-crystalline silica is incorporated into an ink-receiving layer for the purpose of enhancing the ink absorbency of the ink-receiving layer to provide printed dots high in print density and free of feathering or bleeding.
On the other hand, recording media capable of forming images comparable with a silver salt photograph are required to permit forming images excellent in coloring ability of dyes and high in surface glossiness and resolution. Attention is being attracted to alumina hydrate as a component for an ink-receiving layer of recording media capable of providing images comparable with the silver salt photograph. For example, U.S. Pat. Nos. 4,879,166 and 5,104,730, and Japanese Patent Application Laid-Open Nos. 2-276670, 4-37576 and 5-32037 disclose recording media having a layer containing an alumina hydrate of a pseudoboehmite structure as an ink-receiving layer. Japanese Patent Application Laid-Open No. 10-94754 discloses recording media in which alumina hydrate particles contained in an ink-receiving layer.
There has also been recently a demand for recorded images having good shelf stability. Methods for improving the shelf stability of recorded images have also been proposed. As methods for improving, for example, the shelf stability of images to light, Japanese Patent Publication No. 6-30951 discloses recording sheets containing a particular cationic compound, Japanese Patent Publication No. 4-28232 discloses recording sheets containing an aminoalcohol as a light fastness improver, and Japanese Patent Publication No. 4-34512 and Japanese Patent Application Laid-Open No. 11-245504 disclose recording sheets containing a hindered amine compound as a light fastness improver. Japanese Patent Publication No. 8-13569 also discloses the relationship between color change (mainly, a phenomenon that a black ink is changed into a brown color) when a recorded image is stored in a room and color change by ozone gas and that a silica pigment inhibited in surface activity is effective for preventing color change of an image in a room.
However, color fading phenomena, for example, occurring in the case where a recorded image is exhibited in a room, are so various that the whole image is tinged with red or tinted with green, or an imprinted area is yellowed. Causes for the color fading phenomena are not limited to light, and combined factors such as influences of various gases in the air, temperature and humidity are considered. However, there has not been yet known any method for solving fading phenomena of the image resulting from the influences of the combined factors.
The recording media (hereinafter referred to as xe2x80x9crecording media for photographxe2x80x9d) capable of forming images comparable with a silver salt photograph have a structure in which a transparent ink-receiving layer is provided in a thickness of at least several tens xcexcm for the purpose of being adapted to photoprinters by which inks are applied at a high speed and in a great amount, and achieving excellent coloring ability of dyes and high surface glossiness. Such recording media have involved problems that the transparency of the ink-receiving layer is deteriorated to fail to form a bright or clear image, and the ink absorbency is lowered when an additive such as the above-described light fastness improver is contained in a great amount in the ink-receiving layer for the purpose of improving the shelf stability of an image to be formed. In addition, the method of modifying the pigment particles themselves for improving the color change in a room cannot be applied to such recording media. As described above, there is a further problem to be solved from the viewpoint of balance with recording properties in order to impart good fastness properties on images to the recording media for photograph.
It is an object of the present invention to provide a recording medium which can be suitably used in an image forming system using a recording system in which a recording liquid is applied to a recording medium to conduct recording, such as an ink-jet recording system. The recording medium of the present invention permits formation of images high in optical density, bright in color tone and high in resolution, and has excellent ink absorbency. The present invention also provides an image forming process using such a recording medium.
Another object of the present invention is to provide a recording medium which provides excellent shelf stability of an image recorded thereon, and an image forming process using such a recording medium.
A further object of the present invention is to provide a recording medium for photograph, which can provide a print having texture and image quality similar to a silver salt photograph, and an image forming process using such a recording medium.
The above objects can be achieved by the present invention described below.
According to the present invention, there is thus provided a recording medium comprising a base material, and at least one resin selected from a primary amine resin and a secondary amine resin and a hindered amine compound contained in the base material and/or on the surface of the base material.
These compounds may be present on the base material in direct contact with the base material or through another layer coming into contact with the base material.
According to the present invention, there is also provided a recording medium comprising a base material, an ink-receiving layer provided on the base material, and at least one resin selected from a primary amine resin and a secondary amine resin and a hindered amine compound contained in the interior and/or on the surface of the ink-receiving layer.
According to the present invention, there is further provided an image forming process, comprising the step of applying a recording liquid to the surface of the ink-receiving layer of the recording media described above according to recording information to form an image.
According to the present invention, the use of the recording media comprising the two compounds described above can prevent the occurrence of such various color fading phenomena of an image as described above even when images formed thereon by ink-jet recording are exhibited for a long period of time, for example, in a room. The images formed on such recording media thus have very high fastness properties. In particular, the present invention, which can be applied to recording media for photograph, permits formulation of images having texture and image quality comparable with a silver salt photograph without impairing the excellent recording properties thereof. Thus, images having very high fastness properties can be provided by an ink-jet recording system. In addition, an inputting system such as a digital camera is suitably selected, and the ink-jet recording system is used as an outputting system, whereby a print having an image which has texture comparable with that of a silver salt photograph, is superior to a silver salt photograph and also is excellent in fastness properties can be provided by a process more simply and at a higher speed than the silver salt photograph.